NAPA has an automatic to manual conversion kit. Price is about $75.
To fabricate a heat stove:
(1) acquire a 6 inch by 3 inch piece of sheet metal
(2) cut a 1/2 inch square out of each corner
(3) bend up all 4 sides
(4) you now have a rectangular bowl 1/2 inch deep
(5) drill a hole in the center of the bowl
(6) insert a brass fitting in the hole
Heat stove is finished. Install with the open end of the bowl toward the exhaust pipe (or manifold), and attach with muffler clamps. Bend a steel line to attach the brass fitting on the stove to the choke on the carburetor.
Jon.